1. Field of the Invention
The present invention relates to the field of LCD (liquid crystal display) technology, and more particularly to a backlight module, a manufacture method for such backlight module, and an LCD device.
2. Description of Related Art
In the liquid crystal display (LCD) device, a thin type backlight module is usually side-light type. For LED light source having luminous directional, the side-light type can subdivided into direct light type (Side View LEDs) and reflective light type (Top View LED). As shown in FIG. 1, FIG. 1 is a part cross-section drawing of a backlight module of the conventional art. The backlight module 100 use light reflective way and comprises a light guide plate 110, a reflective film 120, a LED light source 130, and a LED circuit board 140. The reflective film 120 and the LED light source 130 are disposed on the LED circuit board 140. The light guide plate 110 is disposed on the reflective film 120. The LED light source 130 is disposed at the side edge of the light guide plate 110, and a reflective surface 131 is disposed on the top of the light emitting surface of the LED light source 130.
In practical applications, when the light guide plate 110 and the reflective film 120 are cutting, there will be some cutting tolerance. In this situation, the reflective film 120 may be shorter than the light guide plate 110, showing as part enlarge portion of FIG. 1. The lights emitted by the LED light source 130 and reflected by the reflective surface 131 will pass through the LED circuit board 140 and reflect again from the bottom of the light guide plate 110 and then enter the light guide plate 110. When the backlight module 100 is used for the LCD device, the LCD device will generate bright dots.
To overcome the bright dots problem, the conventional art use a silicon bar to block the lights. Please also refer to FIG. 2, FIG. 2 is a schematic assembly drawing of the LED light sources, LED board, and the silicon bar shown in FIG. 1. Multiple LED light sources 130 are arranged along the direction of the side of the LED circuit board 140. In addition, a silicon bar 150 is also disposed on the LED circuit board 140 and close to the sidewalls of the LED light sources 130. The silicon bar 150 can block the lights entering to the bottom side of the light guide plate 110. However, due to the silicon bar 150 is long and narrow, it is difficult to align the silicon bar 150 with the side edge of the light guide plate 110 when the silicon bar 150 is attached to the LED circuit board 140. When the silicon bar 150 is displaced toward the light guide plate 110, the silicon bar 150 cannot completely block partial lights reflect down from the reflective surface 131. The partial lights are still possible to enter the light guide plate 110 from the bottom side of the light guide plate 110, and the bright dots will still be generated.